package com.dckj.auto.common.utils;
import java.security.MessageDigest;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.SortedMap;


public class MD5Encrypt {

  public MD5Encrypt() {

  }

  private final static String[] hexDigits = {
          "0", "1", "2", "3", "4", "5", "6", "7",
          "8", "9", "a", "b", "c", "d", "e", "f"};

  /**
   * 转换字节数组为16进制字串
   * @param b 字节数组
   * @return 16进制字串
   * http://www.jq-school.com
   */
  public static String byteArrayToString(byte[] b) {
    StringBuffer resultSb = new StringBuffer();
    for (int i = 0; i < b.length; i++) {
      resultSb.append(byteToHexString(b[i]));//若使用本函数转换则可得到加密结果的16进制表示，即数字字母混合的形式
//      resultSb.append(byteToNumString(b[i]));//使用本函数则返回加密结果的10进制数字字串，即全数字形式
    }
    return resultSb.toString();
  }

  private static String byteToNumString(byte b) {

    int _b = b;
    if (_b < 0) {
      _b = 256 + _b;
    }

    return String.valueOf(_b);
  }

  private static String byteToHexString(byte b) {
    int n = b;
    if (n < 0) {
      n = 256 + n;
    }
    int d1 = n / 16;
    int d2 = n % 16;
    return hexDigits[d1] + hexDigits[d2];
  }

  public static String MD5Encode(String origin) {
    String resultString = null;

    try {
      resultString = new String(origin);
      MessageDigest md = MessageDigest.getInstance("MD5");
      resultString = byteArrayToString(md.digest(resultString.getBytes()));
    }
    catch (Exception ex) {
      ex.printStackTrace();
    }
    return resultString;
  }



  public static String MD5Encode(String origin, String charsetname) {
    String resultString = null;
    try {
      resultString = new String(origin);
      MessageDigest md = MessageDigest.getInstance("MD5");
      if (charsetname == null || "".equals(charsetname))
        resultString = byteArrayToString(md.digest(resultString.getBytes()));
      else
        resultString = byteArrayToString(md.digest(resultString.getBytes(charsetname)));
    } catch (Exception exception) {
    }
    return resultString;
  }

  /**
   * @Author: HONGLINCHEN
   * @Description:支付参数生成签名
   * @param characterEncoding
   * @param parameters
   * @Date: 2017-9-8 10:29
   */
  public static String createSign(String characterEncoding,SortedMap<Object,Object> parameters,String apiKey){

    StringBuffer sb = new StringBuffer();
    Set es = parameters.entrySet();//所有参与传参的参数按照accsii排序（升序）
    Iterator it = es.iterator();
    while(it.hasNext()) {
      Map.Entry entry = (Map.Entry)it.next();
      String k = (String)entry.getKey();
      Object v = entry.getValue();
      if(null != v && !"".equals(v)&& !"sign".equals(k) && !"key".equals(k)) {
        sb.append(k + "=" + v + "&");
      }
    }
    sb.append("key=" + apiKey);
    String sign = MD5Encode(sb.toString(), characterEncoding).toUpperCase();
    return sign;
  }

    public final static String getMessageDigest(byte[] buffer) {
        char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };
        try {
            MessageDigest mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(buffer);
            byte[] md = mdTemp.digest();
            int j = md.length;
            char str[] = new char[j * 2];
            int k = 0;
            for (int i = 0; i < j; i++) {
                byte byte0 = md[i];
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            return null;
        }
    }

  /**
   *
   * @param args
   */
  public static void main(String[] args) {
//    MD5Encrypt md5encrypt = new MD5Encrypt();
    System.out.println(MD5Encode("123"));
  }
}

